yeah, thats what i meant i needed. i have 2 down pipes, each with 3 cylinders and its own "precat" and o2 sensor, then they join together and theres one more sensor, then my main cat. so do i need two simulators? or do i just put it on the back one?

i am adding more o2 to the intake which makes the computer think its running really lean, so i need some way to trick the ECU into thinking it has the perfect amount of o2 coming out. will a simulator do that?